JP2000256576A - Carbon black - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain carbon black having increased dispersibility without adverse effect on its blackness in no need of addition of dispersing agent, oxidation treatment and the like in the carbon black that is used as a black pigment for coloring resins, printing ink, paint and the like. SOLUTION: The objective carbon black has the nitrogen adsorption specific surface area (N2 SA) of 160-330 m2/g and the 24M4DBP absorption (24M4DBP) of 55-95 ml/100 g and satisfies the following formula: (D1/2)/24M4 DBP<=3.21×(CTAB/N2 SA)-2.31 (CTAB is the CTAB specific surface area (m2/g); D1/2 is the half-value width (in nm) of the diameter corresponding to the maximum frequency stokes in the diameter distribution corresponding to the agglomeration Stokes).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to furnace carbon black used as a black pigment for coloring resin, printing ink, paint and the like.

[0002]

2. Description of the Related Art Carbon black used for pigments is important not only for its blackness but also for its kneading with a resin and the dispersibility of carbon black in products. However, the blackness and the dispersion method are in a trade-off relationship, and it has been difficult to achieve both blackness and dispersibility. Blackness and dispersibility are highly correlated with the particle size or structure of carbon black.The smaller the particle size and structure, the higher and better the blackness, but conversely, the dispersibility lowers the shear when kneading. It is known that it becomes worse due to the like. Therefore, there is a method of adding a dispersant as a post-treatment of carbon black for the purpose of improving dispersibility. However, according to this method, depending on the amount added,
Blooming may occur on the surface of the molded article, and it was not a preferable method.

Further, Japanese Patent Publication No. 46-18368 and Japanese Patent Publication No. 52-13808 propose a method of oxidizing the surface of carbon black with ozone or hydrogen peroxide. However, such a method
As the equipment becomes more complicated, the cost increases, and the treated carbon black has problems such as not being compatible with all resin blending systems.

[0004]

An object of the present invention is to provide a carbon black used as a resin-colored black pigment,
Without adding a dispersant to carbon black,
An object of the present invention is to provide a carbon black having improved dispersibility without oxidizing the surface of the carbon black and without impairing the blackness as a pigment.

[0005]

Means for Solving the Problems The inventors of the present invention have made intensive studies on carbon black which can maintain the blackness and improve the dispersibility. As a result, the surface of the primary particles of the carbon black has been smoothed and the 24M4DBP has been increased. Or, by reducing the specific surface area, the kneading share to the resin can be increased, and the dispersibility of carbon black can be improved. The present inventors have found that high dispersibility can be imparted without impairing the blackness level, and the present invention has been accomplished.

That is, the carbon black of the present invention comprises:
Nitrogen adsorption specific surface area (N ₂ SA) is 160 to 330 m ² /
g, 24M4DBP absorption amount (24M4DBP) is 55 to
A carbon black characterized by satisfying the following (Equation 1) at 95 ml / 100 g. (D _1/2 ) /24M4DBP≦3.21× (CTAB / N ₂ SA) −2.31 (Formula-1) [In the formula-1, CTAB is a CTAB specific surface area (m ² / g)
And D _1/2 is the half width (n) of the maximum frequency Stokes equivalent diameter in the aggregate Stokes equivalent diameter distribution by the centrifugal sedimentation method.
m). ]

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The carbon black of the present invention has a nitrogen adsorption specific surface area (N ₂ SA) of 160 to 330 m ² / g.
It is necessary to be. If the N ₂ SA is less than 160 m ² / g, the dispersibility is improved, but the blackness is reduced.
If it exceeds m ² / g, the degree of blackness improves, but the dispersibility decreases, which is not preferred. Preferably, 200 to 300 m ²
/ G. Note that the value of N ₂ SA is determined according to ASTM D30.
It is a value measured according to 37-88. The carbon black of the present invention has a 24M4DBP oil absorption of 55 to 55.
It is necessary to be 95 ml / 100 g. 24M4
If the DBP oil absorption is less than 55 ml / 100 g, the dispersibility decreases, while if it exceeds 95 ml / 100 g, the blackness decreases, which is not preferable. Preferably, 65 to 85 ml /
100 g. The value of 24M4DBP is AST
It is a value measured according to MD3493-85a.

Further, the carbon black of the present invention has a (D
_The relationship between the agglomerate Stokes equivalent diameter distribution index represented by _1/2 ) / 24M4DBP and the surface roughness index of the primary particle diameter represented by (CTAB / N ₂ SA) is represented by the above-mentioned (formula-1).
Needs to be satisfied. When (D _1/2 ) / 24M4DBP is larger than 3.21 × (CTAB / N ₂ SA) −2.31, it is not preferable because dispersibility is deteriorated or blackness is lowered. Note that, in (Equation-1), CTA
B indicates the CTAB specific surface area (m ² / g), and AS
It is a value measured according to TM D3756-80.
Also, D _1/2 indicates the half width of the maximum frequency Stokes equivalent diameter (nm) in aggregates Stokes diameter distribution by centrifugal sedimentation method, the D _1/2 is centrifugal sedimentation type particle size distribution measuring apparatus Is a value obtained by measuring the distribution of the equivalent Stokes diameters using the formula, and calculating the value of half of the maximum frequency equivalent Stokes diameter in the distribution.

As a specific method for measuring the Stokes equivalent diameter distribution, for example, first, for example, LACONANUF
"BRANSONIC 22" manufactured by ACTULINE
A sample solution is prepared using an ultrasonic disperser such as “0”. The sample solution was prepared by dispersing 5 mg of carbon black in a 20% ethanol aqueous solution containing a few drops of a surfactant to prepare a 0.01% by weight ethanol aqueous solution of carbon black, and then dispersing the solution for 5 minutes using an ultrasonic disperser. , For example, B
Using a centrifugal sedimentation type particle size distribution analyzer such as “BI-DCP PARTICLSIZER” manufactured by ROOK HAVEN INSTRUMENTS, the rotation speed is 8000.
The sample solution is injected into an apparatus set to rpm, and the Stokes equivalent diameter distribution of aggregates can be measured.

If the carbon black of the present invention satisfies (Equation 1), the values of CTAB and D1 _{/ 2} are not limited, but the preferred CTAB values are 220 to 260.
The value of m ² / g and D _1/2 is 25 to 40 nm. The carbon black of the present invention has a combustion zone for generating a high-temperature combustion gas, a raw material hydrocarbon introduced into a high-temperature combustion gas stream, a reaction zone for converting the raw material hydrocarbon into carbon black by a thermal decomposition reaction, and a reaction by water cooling. In a process having a reaction stop zone to stop, it can be manufactured by controlling various conditions such as combustion conditions, high-temperature combustion gas flow rate, feedstock introduction conditions, and reaction stop time.

Specifically, in order to form a combustion zone or a high-temperature combustion gas, air, oxygen, or a mixture thereof, and gaseous or liquid fuel hydrocarbon are mixed and burned as the oxygen-containing gas. As the fuel hydrocarbon, hydrogen, carbon monoxide, natural gas, coal gas, petroleum gas, petroleum-based liquid fuel such as heavy oil, and coal-based liquid fuel such as creosote oil are used. The combustion conditions are controlled in the range of 1500 to 1900 ° C. The raw material hydrocarbon is sprayed from a burner provided in parallel or perpendicular to the direction of the high temperature combustion gas flow obtained in the reaction zone, and pyrolyzed to obtain carbon black. More specifically, a high-temperature combustion gas flow having a gas flow rate in the range of 200 to 600 m / s is divided and introduced by two or more burners. Preferably, the gas flow rate is 500 to 600 m / s,
The feed hydrocarbon is dividedly introduced by six or more burners perpendicular to the high-speed and high-temperature combustion gas flow controlled at 1700 to 1900 ° C. In order to improve the reaction efficiency, a throttle section is generally provided in the reaction zone, and the degree of the throttle is 0.2 to 0.
8 As raw material hydrocarbons, aromatic hydrocarbon oils such as anthracene, petroleum hydrocarbon oils such as creosote oil, EHE oil (sub-oil for ethylene production), FCC
Petroleum heavy oil such as oil (fluid catalytic cracking residue) is used. The reaction stop zone is provided with a high-temperature reaction gas of 800 to 100.
In order to lower the temperature to 0 ° C., water spraying is used. The time from the introduction of the raw materials to the termination of the reaction was controlled in the range of 3 to 50 ms. The cooled carbon black can be subjected to a known process of separating, recovering, granulating, and drying the gas.

The carbon black of the present invention is used for colorants such as plastics and pigments.
As the plastic, conventionally known polyvinyl chloride,
Polyethylene, polypropylene, polystyrene, AB
S, polycarbonate, polyester and the like,
As a coloring method, a dry color, a paste color, a liquid color, a master batch, and a colored pellet can be used. Among them, a master batch and a dry color method are generally employed. For example, when making a master batch, the carbon black in the master batch is
When the final product is used, the carbon black in the product is used in an amount of 0.5 to 2% by weight.

[0013]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited to these. Examples 1 to 3 800 m inside diameter provided with air introduction duct and combustion burner
m, a combustion zone having a length of 1600 mm, an inner diameter of 145 m connected from the combustion zone and having a raw material nozzle penetratingly connected from the periphery.
m, a material introduction zone comprising a narrow diameter portion having a length of 1000 mm,
400 mm inside diameter, 3000 m long with quench device
m using the carbon black reaction furnace shown in FIG. 1 in which the rear reaction zones were sequentially joined, using heavy fuel oil C as fuel and creosote oil as raw material hydrocarbon, and using the carbon black reactor under the conditions shown in Table 1. Was manufactured. Table 2 shows various properties of the obtained carbon black.

The properties of the obtained carbon black were measured and evaluated by the following methods. (1) CTAB: Measured according to ASTM D3756-80. (2) N ₂ SA: Measured according to ASTM D3037-88. (3) 24M4DBP: ASTM D3493-85a
It measured according to. (4) 5 mg of D _1/2 carbon black sample was precisely weighed, and a surfactant (S
NONIDET P manufactured by IGMA CHEMICAL
-40) was added to a 20% aqueous ethanol solution to which 3 drops were added.
After preparing an aqueous ethanol solution containing 0.01% by weight of carbon black, an ultrasonic disperser (LACOMMANUFACTUR) was used.
The mixture was dispersed for 5 minutes using BRANSONIC 220 (manufactured by INE Co., Ltd.) to obtain a sample solution. Next, a centrifugal sedimentation type particle size distribution analyzer (BROOK HAVEN INSTRUUM)
EN-TS, BI-DCPPARTICLSIZE
The rotation speed of R) is set to 8000 rpm, and 10 ml of a spin solution (pure water) is added thereto, and then 1 ml of a buffer solution (20% ethanol aqueous solution) is injected. Then
Inject 1 ml of the sample solution prepared above into a particle size distribution measuring device with a syringe, simultaneously start centrifugal sedimentation, measure the aggregate Stokes equivalent diameter distribution, and determine the half-width of the maximum frequency Stokes diameter in the aggregate Stokes equivalent diameter distribution. _{Was set} to D1 _{/ 2} .

(5) PVC blackness 0.3 g of carbon black is added to 30 g of PVC resin, and the slit width is 0.3 m at a roll temperature of 120 to 125 ° C.
2 rolls manufactured by Sakurai Seisakusho (Model:
After kneading for 7 minutes with a mixing roll), a sheet was prepared. This sheet was pressed at 170 ° C. under the conditions of ^{3 to} 8 kgf / cm ² to prepare an evaluation sample. The evaluation criteria were carbon black manufactured by Mitsubishi Chemical Corporation, “# 45” and “# 99”.
The blackness of the evaluation samples obtained by the same method for the three types “0” and “# 600” was determined to be 10, 14, and 20 points in order, and the blackness of the sample to be evaluated was visually evaluated by comparing them. . The intermediate carbon black for resin coloring is good if the blackness level is 13 points or more, and the larger the numerical value, the better the blackness.

(6) PE dispersion index <Preparation of evaluation sample> LDPE resin (LF440HB manufactured by Nippon Polychem Co., Ltd.) 101.49 using a Banbury mixer (model: B-250) manufactured by Toyo Seiki Seisaku-sho, Ltd.
g, calcium stearate 0.87 g, Irganox 1.39 g and carbon black 69.44 g.
The mixture was kneaded at 5 ° C. for 7 minutes (40 wt% master batch was prepared). Then, using a two-roll mill (6 inches) set at 130 ° C., 58.3 g of LDPE resin (LF240 manufactured by Nippon Polychem Co., Ltd.), 0.2 g of calcium stearate, and 1.5 g of the 40 wt% master batch prepared above. Was kneaded for 10 minutes, formed into a sheet having a thickness of 0.5 mm, and small pieces of 3 mm square were cut out. Then, a small piece of 3 mm square was sandwiched between glass plates on a hot plate set at 150 ° C., and a load of 5 kg was applied for 3 minutes to prepare a film of an evaluation sample.

<Evaluation of Dispersibility> The film of the obtained evaluation sample was observed with an optical microscope at a magnification of 20 times, and an image processing analyzer (MKSIPS-1000) manufactured by Mitsubishi Chemical Corporation was used. The total area of the particles was determined, and then the ratio of this area to the observation field area was calculated. This was observed at 12 or more places on the evaluation sample film and 100,000 times the average value calculated as the dispersion index. The smaller the value is, the shorter the kneading time can be, and the production cost can be reduced and the productivity can be improved. Also, regarding the quality of resin colored molded products,
It shows that the decomposability is good because it is possible to improve the gloss on the surface of the molded product and to prevent the occurrence of lumps with poor dispersion, and furthermore, it is possible to develop blackness in a light color system.

Comparative Example 1 Commercially available carbon black "# 960" manufactured by Mitsubishi Chemical Corporation
Table 2 shows the results of measurement and evaluation of
2 is shown. It can be seen that the PVC blackness is good but the dispersibility is poor. Comparative Examples 2-3 Using the same reactor as that produced in Example 1, carbon black was produced under the conditions shown in Table 1. Table 2 shows the results of measuring and evaluating various properties of the obtained carbon black in the same manner as in the examples. It can be seen that the carbon black of Comparative Example 2 has good dispersibility but poor blackness. Further, it can be seen that the carbon black of Comparative Example 3 has good blackness but poor dispersibility.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

The carbon black according to the present invention is excellent in both blackness and dispersibility without adding a conventional dispersant or performing an oxidation treatment or the like, and is suitable for use in resin coloring, printing inks and paints. It can be suitably used.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a carbon black reactor in an example.

[Explanation of symbols]

 Reference Signs List 1 air 2 heavy oil C 3,4 creosote oil 5 reaction stop water A combustion zone B material introduction zone C reaction zone

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shuichi Yoshimura 1 Toho-cho, Yokkaichi-shi, Mie F-term in Yokkaichi Office of Mitsubishi Chemical Corporation (reference) 4J002 AA001 DA036 FA096 FD096 GJ01 GT00 4J037 AA02 BB05 BB30 BB33 BB36 DD05 DD07 DD17 FF05 FF15

Claims (1)

[Claims] 1. A nitrogen adsorption specific surface area (N ₂ SA) of 160
３３０330 m ² / g, 24M4DBP absorption (24M4D
BP) is 55 to 95 ml / 100 g, and the following (formula-1)
Carbon black characterized by satisfying the following. (D _1/2 ) /24M4DBP≦3.21× (CTAB / N ₂ SA) −2.31 (Formula-1) [In the formula-1, CTAB is a CTAB specific surface area (m ² / g)
And D _1/2 is the half width (n) of the maximum frequency Stokes equivalent diameter in the aggregate Stokes equivalent diameter distribution by the centrifugal sedimentation method.
m). ]